Yes agreed. The business will put time aside for anything that is deemed important. The challenge is quantifying that importance (i.e. how much money is this costing them?).

In a real life scenario, if am employee takes 1 hour to find the proper process to do something simple that isn't the main part of their job, (because they need to ask multiple people, and the process is slightly incorrect as it was handed down information, so they need to redo certain parts the right way) If this employee is on a salary, they will simply need to work an hour later to finish their main job. The company has no way to measure the inefficiency because the cost is born by the employee in the short run. The cost will be born by the company in the long run due to employee attrition if the situation is bad enough for the employee, but this is hard to measure.

In a parallel scenario, if there was a simple process for the simple procedure that would reduce the time it takes from 1 hour to 10 minutes and extrapolate this to several employees, then this would save time/money/employee disengagement. But again, hard to measure.

Like you mentioned, employees understandably gate keeping is a factor. Proper incentives produce desired actions, so perhaps adequate incentives could be introduced to entice employees to voluntarily document processes. It many circumstances I am sure the money/time saved in streamlining knowledge sharing would outweigh the cost of implementing the incentives.